Triadenum tubulosum (Walt.) Gleason

Locations ofTriadenum tubulosum (Walt.) Gleason in Virginia

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Botanical Name
Triadenum tubulosum (Walt.) Gleason
Common Name
Lesser Marsh St. John's-wort
Hypericum tubulosum Walter
Flora of Virginia Name/Status
Triadenum tubulosum (Walt.) Gleason
This species can be readily distinguished from its similar congeners Triadenum virginicum and T. walteri by the lack of punctate glands on its foliage. Its sessile leaves are somewhat variable; the upper leaves of well-grown plants are often rounded to somewhat cordate at base while lower leaves and leaves of small plants are usually cuneate to a narrower base.

The proper disposition of plants in the genus Triadenum may be still unresolved, as they have been recently treated in both Hypericum and Triadenum. Based on a comprehensive phylogenetic study of Hypericum (sensu lato), Nürk et al. (2013, Molec. Phylogen. & Evol. 66: 1-16) included Triadenum in Hypericum, but the position of Triadenum as a somewhat basal clade and the inclusion of Triadenum japonicum suggests that the fairly ancient, eastern North American - east Asian vicariance had elements that were clearly similar to one another and distinct from other Hypericums long ago. The morphological distinctions of Triadenum lend further credence to its treatment as a separate genus.
Bottomland forests and swamps, usually in seasonally flooded sloughs and depressions. Widespread, but infrequent to rare in the southern and central parts of the inner Coastal Plain and outer Piedmont. Very rare elsewhere.
Native Status

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